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Drive Sections v8i

Intro...

These steps should be performed before cross sections are transferred to MicroStation.  If drive sections are needed after the sections have been worked on in MicroStation, then those changes will be lost.  Make a strong attempt to identify all areas where a drive might be.  It is easier to delete a drive section than to move sections in MicroStation from sheet to sheet just to allow for a drive section which was not anticipated.

For the sake of this documentation, Simple Drives are normal (90 degree orientation) to the road design.  Skewed Drives are not normal and are either skewed ahead or back from the edge of proposed pavement.  Complex Drives are those who's alignment would describe a curve, skewed approach or not.  All drive alignments should be normal between pavement edges, this insures that a 12' roadway lane always measures 12' on a cross section.

Create a drive model "MC_M  Drives" for each road that have skewed and/or complex drives on it.


Simple Drives...

Advance to Complex Drives if there are no Simple Drives.

It is necessary to define the drive stations on the reference line.  Select Modify => Edit Point => Interpolate a Point onto a String... to create all the odd drive stations on the reference line.  Note the locations of all these odd stations, they will be needed for the generation of sections.  Delete all the construction lines if any were used.  Repeat for every road that will have odd drive stations.



Complex Drives...

Advance to Skewed Drives if there are no Complex Drives.

It is necessary to determine the drive stations on the reference line.  Create construction drive center lines in MX for the portion of each drive that will intersect the reference alignment using the string label "L".  Make sure each drive construction string is normal to and crosses the reference line.  Select Modify => Edit Point => Interpolate a Point onto a String... in conjunction with the Intersection Point Selection Method to create all the odd drive stations on the reference line.  Note the locations of all these odd stations, they will be needed for the generation of sections.  

Create drive alignment reference strings "MC_D" using Quick Horizontal Alignment for each complex drive that you have for each road (Classic Alignment also works fine).  Start each drive alignment at the reference line and project away toward each complex drive.  Use the Snap feature to select the odd station points that were just interpolated onto the reference alignment.  Delete all the construction lines when done.

Repeat for every road that has complex drives.


Skewed Drives...

Advance to Profiling Drives and Section Generating if there are no Skewed Drives.

Thanks to v8i for allowing the use of both MicroStation and MX tools simultaneously.  Construction lines makes this process much easier.

Begin by using MX tools to create construction lines for the skew portion of each skewed drive.  The Construction PSM (Point Selection Method) Divide a Line is ideal for determining the centerline of a skewed drive.  In the following illustration, notice the solid gray line segment splitting the existing drive pavement:

MX screen capture

These skewed drive construction centerlines need to be extended to intersect the roadway edge of pavement.  Using MicroStation and Accudraw, trace over the new skewed drive centerlines to align the Accudraw compass with the skewed construction lines.  Place a point to extend this construction line past the edge of pavement.  Now there should be an intersection with this skewed drive construction line and the proposed road's edge of pavement.

MX screen capture

The final construction element needed describes the normal portion (within the pavement edges) of the skewed driveway alignment.  Using MicroStation, create another construction element with the Perp hit code from the roadway reference line to the intersection (the Intersection hit code) of the skewed drive construction line and the edge of pavement.  If the Perp hit code does not function from the reference line, then use the edge of lane on the opposite side of the road.  This concludes the creation of the construction lines for this section.

MX screen capture

Create skewed drive centerlines in MicroStation for each skewed drive from the construction lines just created.  Start each line from the proposed roadway center line and project away toward each skewed drive.  Delete all the MX and MicroStation skewed drive construction lines.

MX screen capture

Use the MX Conversion toolbar to convert the skewed drive centerlines to the MX Roadway (Other - 1) feature strings.  Refer to MX Conversion for details transferring MicroStation elements to MX.

In MX, select Modify => Edit Point => Interpolate a Point onto a String... in conjunction with the Intersection Point Selection Method to create all the odd drive stations on the reference line.  Note the locations of all these odd stations, they will be needed for the generation of sections.  Repeat for every road that will have odd drive stations.


Profiling Drives and Section Generating...

Profile (long section) the complex drive M strings over the existing triangles creating OC_E strings within the drive model.  Profile (long section) the skewed drive centerlines over the existing triangles creating OE__ strings within the drive model.  Triangle the design model.  Profile (long section) the complex drive M strings over the design triangles creating OC_D stings within the drive model.  Profile (long section) the skewed drive centerlines over the design triangles creating OD__ stings within the drive model.   Create an input file to accomplish the triangulating and profiling at the same time, refer to this Sample Input File.  It's much easier than the interactive option.  Input this drive file in MX.

Create
a cross section model and set the Model Defaults to XSU.  Cross Section the roadway reference master string using a constant chainage (station) Interval (i.e. 50' or 20m) over both the existing triangles and over the design model storing both the E and D sections in the section model.  Also cut cross sections at all of the odd drive stations (Simple, Complex and Skewed) so that there is a cross section at every drive.  See MX Cross Sections for more details.

Draw these cross sections, refer to XS-MS for assistance creating a cross section drawing input file.  Export this cross section drawing to a Native DGN format.


Draw Drive Profiles in MX and Export to MicroStation...

If any of the drive design "O" strings extend beyond the limits of the design model, then those points outside of the design model are assigned null elevations.  Delete these null points prior to drawing their profiles.

Every drive profile (both Complex and Skewed drives) may be drawn using the MX Profile wizard.  For any drive profile who's reference string is a master alignment (such as Complex drives) use the NHProfile Add-In, it is simpler than the MX Profile wizard.  Note that the NHProfile Add-In does not allow feature reference strings.

When the MX Profile wizard is used to draw a drive profile, specify the existing and proposed  "O" strings as the profile strings.  A scale of 1 is desired for transfer to MicroStation 10 scale cross sections.  Export each drive profile to a Native DGN format with a unique file name ( so that subsequent profile drawings don't over write this one). 

When NHProfile is used to draw a drive profile, specify the drive "M" string as the reference string and the "O" strings for the proposed and existing profile strings.  Create a new drawing .DPW file for each drive profile.  A scale of 1 is desired for transfer to MicroStation 10 scale cross sections.  Export each profile to a Native DGN format with a unique file name.



Transfer the roadway cross sections to MicroStation, refer to MX cross-sections to MicroStation.  Transfer the complex drive profiles to MicroStation, refer to Transferring MX profiles to MicroStation.

Edit MicroStation data...

Open the first drive profile (section) and set the main cross section drawing as a Reference file.  Any drive profiles on the left of the Reference string will need to be mirrored.  Every right side drive profile should continue to project from left to right.  With the main sections displayed, Move the profiles to the corresponding cross section location so that the grids line up.  Repeat this for each drive profile.

Use Change Element Attributes to set your level, line style, and line color from the old ground section.  Apply these attributes to each old ground drive profile.  Use Change Element Attributes again to set your level, line style, and line color from the proposed ground sections.  Apply these attributes to each proposed drive profile. 

After all the drive profiles have been moved to the appropriate locations over the cross sections, then open the main cross section drawing in MicroStation and attach all the drive profiles as reference files.  All of the drive profiles should display in the proper locations.  Then Delete all the sections (old ground and proposed ground) where a drive is going to go.  Now copy the drive profiles (old ground and proposed ground) to the cross section drawing.  Repeat these steps for each drive profile that you attached as a reference file.

Add text to each drive section indicating that it is either a Simple, Complex or Skewed section.  Detach all the drive profile drawings from the main cross section drawing.

On the cross section drawing, draft each drive profile using standards defined in the Driveway Manual.






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